mustang slayer

Hello fellow forum members! I'm the proud owner of two 1970 LS-5 454 390 horse BB cars and am constantly fending off negative comments about the limited performance and cast iron monster perception of this model year, mostly by other vette owners as opposed to just muscle car enthusiasts in general. Similiar high performance cars of the year 1970 seem to be held in high esteem with lower horsepower and torque ratings and same cast iron block, such as Buick 455 369Hp 510 torque, Olds 442 370 hp 500 torque, pontiac GTO Ram air three rated at 366 Hp at 445 ft. pounds of torque. I think this all got started in 1969 when all the buzz talk was about the soon to be LS-7 to be rated at 465 hp. which never did materialize and the very limited production of the LS-6 rated at 450 Hp. available only in the chevelle of that model year 1970. So the arrival of the LS-5 390 hp car was a big let down even though it still matched up favoribly with other big block production of the year. Also The LS-5 for 1970 was quite unique in that it was really the only stock high performance 454 produced in a strike year with production of only 4,473 units made. And at 10.25 to 1 at 390 Hp 500 ft. pounds of torque was just a shadow of its self by 1972 thru 74 with low compression ratings and limited torque and horsepower ratings at a paltry 270 Hp. Folks seem to lump all 454 LS-5 cars to gether 70-72 and there seems to be the problem for the 1970 390 hp LS-5 and thats why i consider it the most disrespected BB high performance engine of its time, the rodney dangerfield of big block vettes if you will.

73 LS-4

I think your missing something in the translation here, even the lowest rated LS-5 and 4's are 270hp net. Your 390 hp gross is only about a 300 hp net number. for example the 365hp rating of a 71 LS-5 is actually only a 285 net rating, so at the most your only talking a 30 hp net difference going into the low compression era.


Pat Kunz

mayberg

I suppose if your ignition system is up to spec, you've done the Lars-tuning, and you're running the proper octane fuel, then you're probably pulling enough power out of a stock 1970 LS5. I drove one with a 4-speed learned to respect it. The 1970 is a great car for all the reasons you mentioned - plus it's quite light.

I usually shut them up by challening them to a burn-out contest. Make sure you're using poly engine mounts - ask me why.

mustang slayer

Most stock LS-5 1970 390 Hp cars with limited power options like mine, power steering only dyno well over 300 net horsepower if in good mechanical condition and tuned right. Everyone knows insurance companies were pressing for lower horsepower ratings in 70 and true ratings were reduced. 72 thru 74 LS-5 , LS-4 cars were more accurately rated and at 270 Hp you can see and feel the difference if you have driven them both like I have, I think your point is common thinking however that a 454 is a 454, no matter what.

docmow

now if tou want a true rodney you could own a 1976 with a vega
sterring wheel not that i do not love mine
docmow

73 LS-4

I'm not saying that the 70 isn't the most powerfull of the hydraulic lifter big blocks, I'm just saying that I haven't seen any evidence, dyno or 1/4 mile times that prove it's all that more more powerfull then the rest of the L-36, LS-5, LS-4 group. You always seem to exclude the 71 LS-5 from the equation which was a 365gross/285 net engine?. I'm not trying to start an argument here or anything, I just don't take things at face value, I want to see the evidence behind it.


Pat Kunz

wildman378

the 70 454 has only slighty more power over the 270 rated 72 the drop was only in 71 really and it went from 390 to 365 the drop in 72 was only from gross rating to net.

your 70 produces about 300 net. which means it shoulda put down about 250 rwhp in 1970

Jay M

But when you finally do rebuild it..... Then you can make some huge power all while looking stock on the outside.

~Jay

PRNDL

rodney dangerfield? I refer to my L-36 bigblock (427/390) as a "stationwagon engine" because, well, that 427 engine was used in a few stationwagons. It was never a high po engine.

mustang slayer

I think I'm proving my point here, I don't want to get tunnel vision on just gross HP versus Net HP since there seems to be more to the equation here. lower compression pistons 8.5 compared to 1970 10.25 high compression makes a differance as does the torque ratings of 500 ft. pounds to 390 ft. pounds in the 72 model car unless theres some gross to net variable there that you want to talk about as well.Unless you have driven both cars its a mute point anyway, no amount of dyno tests or quarter mile results equal the actual drive experience. And weren't the later 454's choked down with smog and emmissions equipment that I have read about.

wildman378

dude was it really? hmm I'll never look at our 68 bb the same way again well if you ask me none of the c3 bb's that were stock I've driven seemed like monsters. I've driven all versions of the 427 used in 68 & 69 and a 70 bb and a 72 none were what I expected. All of the 68 & 69's had more to offer than the 454s though.

73 LS-4

Well yea, that is a gross to net conversion as well.


Pat Kunz

mstanton

I think that the change from gross to net does confuse the issue. In fact there was a real hp loss between all years (70-72) and all engines with the biggest from 70 to 71. The loss was pretty small with only a small change in performance. There is a guilt by association though. The 427/390hp L-36, being lump in with all the other 427s, gets more respect then the 454/390hp 70 LS-5.

mustang slayer

Hey, Thanks for all the threads I appreciate all your veiw points and I really respect the forum opinions, thanks again!

turtlevette

let me get this straight....

You own 2 really nice cars and you want us to feel sorry for you because they aren't nicer?

jr9170

As a 70 454/390 owner and ex 69 owner the 68-69 BB is a little more desirable right now but the 70-72 454 is beginning to be recognized.I love my 70 and it is a blast ot drive...So enjoy and drive...JERRY

ngcolby

Hmm...lets see here. 454 Big block vs L48... I'll trade ya...I'll even throw in a case of beer!

Scottys78

Just can’t get respect